Fluoroelastomers, particularly perfluoroelastomers containing a tetrafluoroethylene (TFE) unit, show excellent chemical resistance, solvent resistance, and heat resistance, and thus are widely used as, for example, sealants in severe environment such as in the fields of aerospace, semiconductor manufacturing devices, and chemical plants.
One known technique to improve the required characteristics of sealants is to add filler to fluoroelastomers.
In order to provide a seal for semiconductor manufacturing devices which has heat resistance, low gas permeability, and stability against plasma irradiation in oxygen or CF4 atmosphere, and which does not generate dust, Patent Literature 1 proposes adding 1 to 50 parts by weight of silica and 1 to 10 parts by weight of an organic peroxide to 100 parts by weight of a fluoroelastomer.
In order to improve the plasma resistance and reduce generation of particles after plasma irradiation, Patent Literature 2 proposes adding fine particles of aluminum oxide having an average particle size of not greater than 0.5 μm to a crosslinkable fluoroelastomer component.
In order to provide a peroxide-vulcanizable fluoroelastomer white blend composition that does not impair the compression set, Patent Literature 3 proposes adding, to a fluoroelastomer, white carbon ultrafine particles the 4 to 5 wt % aqueous solution of which has a pH of 9 to 12.
In order to provide a fluoroelastomer composition which maintains heat resistance and processability under the environment where the workpiece is directly exposed to plasma, such as the inside of a dry-etching device, has little weight change by exposure to both fluorine plasma and oxygen plasma in the production step of a semiconductor, and does not generate foreign objects (particles) at these steps, Patent Literature 4 proposes adding, to a fluoroelastomer, at least one selected from the group consisting of isoindolinone pigments, quinacridone pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, amine antioxidants, phenol antioxidants, sulfur antioxidants, and phosphorus antioxidants.
Patent Literature 5 discloses, as filler which has little weight change by oxygen plasma irradiation and CF4 plasma irradiation, a filler containing a synthetic high molecular compound having an amide bond in the main chain or a synthetic high molecular compound having an imide bond in the main chain. The literature also discloses adding this filler to a crosslinkable elastomer.